This month, I'm going to discuss a genetic abnormality that occurs in some lines of nubian goats. It is called G-6-S. I recently had a customer ask me if I tested for this condition, and I had to tell her that I had never heard of it. I immediately called my veterinarian, who also said she'd never heard of it. Now I definitely consider my vet to be one of the best (if not THE best) veterinarians in the country. So I can attest to the fact that in many areas of the country, G-6-S is unknown. My next step was to get on the Internet and ask what the darned condition was. I received responses from Caroline Lawson of Texas A&M University and from Deena Sansone of Kaapio Acres in Michigan. The following information is taken from private correspondence from these two ladies, who were gracious enough to educate me on this matter.
Caprine mucopolysaccharidosis-III, most commonly called G-6-S, is a genetic defect that was discovered in the Nubian breed by Michigan State University in the 1980’s, when a young buck kid was brought to the large animal clinic with neurological problems. The animal died before reaching a year old.In effect, this is an inherited lysosomal storage disease of
Nubians and some other species (including man). It is caused
by an enzyme deficiency that allows certain carbohydrate
molecules to accumulate in nervous and other tissues, resulting in
dysfunction. This is a simple-recessive-gene, so that a Carrier bred to a Carrier will produce 25% Normal, 50% Carriers, and 25% Affected animals. A Carrier bred to a Normal will produce 50% Normal and 50% Carriers.
Symptoms of Affected animals include death by 3 to 4 years of age, small stature, lack of muscling, immune system problems, heart problems, difficulty in conceiving, miscarriages, stillbirths, and difficulties in maintaining pregnancies. Michigan State University discovered that of the animals they tested, 25% were Carriers. I would imagine that the animals they tested had a preponderance of sickly specimens. Still - 25% carriers is really significant. So it would behoove all of us Nubian breeders to test for this condition and eliminate it from our herds.
It is best to use a Normal buck and only Normal does in your breeding program. However, Michigan State University and Texas A&M do offer the following advice to those herds that have some Carriers. Carrier does can be used with selective breeding. Breed only to Normal bucks, and have the kids tested. Cull any buck kid that does not test normal. If your funds are limited and you can only afford to have a few animals tested (the test is costly), make certain to get your buck tested. I would offer this additional advice - use older does and/or does from proven lines. For those of you interested in testing your animals, the test is done by Texas A&M University, with Dr. Lloyd Sneed in charge. It is a blood test and is very accurate. The results will come back as Normal, Carrier, or Affected. Normal means the animal being tested does not possess this genetic abnormality; Carrier means the animal has the defective gene; Affected means the animal being tested has the defective gene and is showing symptoms.
If this all sounds ominous, the good news is that the affliction is not contageous. Since it is inherited, it can be eliminated by selective breeding and culling. Of course, it is better to avoid carriers altogether in your breeding program , if possible. I must admit I was relieved that the animals I had sold tested Normal. But you can bet your sweet bippy I'm testing my new little buck just to be certain that I have no Carriers.